cliff. it looks like it came from a residence of a -- it was somebody who lives up there that works for the observatory and the uc school system. >> reporter: some visitors were stunned by the circumstances. >> i had near misses on the way up and the way back with people crossing over to avoid bicyclists and other things. so i don't know why? it's hard to believe that someone would actually have that kind of an accident if they're used to driving up here. but it happens. >> reporter: other visitors said they considered coming up tomorrow because of the possibility of snow. but not after this accident. >> especially icy or snowy. it's hard enough just driving when it's dry but when it's snow, the switch backs and the winding roads just becomes very dangerous. >> and within the past 45 minutes emergency vehicles and some of the workers began leaving the scene. and at this point officials will only say the investigation is ongoing. live near mount hamilton, robert handa. >> reporter: san franci